Finns call on cell phones to monitor traffic jams

Pilot program tracks signal movement

Published 10:00 pm, Tuesday, July 8, 2003

HELSINKI, Finland -- As if today's cell phones were not crammed enough with features, the famously wired Finns now look to be adding another: traffic congestion deterrent.

Using the signals from individual motorists' mobile phones as beacons, government researchers charted vehicular traffic patterns along stretches of road in and around Helsinki, the capital.

The Technical Research Center, the Finnish agency that published an evaluation of the technology this week, found it useful for helping to prevent traffic jams and urged that it be expanded nationally.

The center said the data it obtained would be useful in issuing travel advisories that authorities could transmit for use in TV and radio broadcasts.

A joint pilot project of the Finnish Road Administration and a mobile phone operator, Radiolinja, the system tracks cellular phones that pass between measuring points spaced 3 miles apart.

The data was displayed on a Web site during last year's trial, offering real-time information on traffic congestion, the speed of traffic flow and estimated travel times.

"You can plan your driving and avoid the worst rush hour, decide on alternate routes, predict when you'll arrive at work and when to heat up the sauna," the road administration said. It is seeking funds to continue and expand the project.

Traditional traffic measurements work by simply counting the number of vehicles that pass a given spot on the road, typically using a camera or sensors embedded in the road or on a nearby pole.

By using cellular phones, the system can monitor how long it takes for cars to travel a stretch of road in real time and provide it instantaneously.

But the system isn't perfect.

"There will be errors, of course -- if a bus goes by with 30 phones in it, the system will register them all as individual vehicles. Or if somebody is picking berries in the woods, it will show up as a stationary item," said Timo Karhumaki, the project's manager.

So far, the administration has developed a formula for calibrating the figures by first watching the real amount of traffic, then comparing it with the data collected from mobile phones. Then, they figure out a weighting factor to correct for the errors.

In order for the system to provide reliable data, researchers say at least 5 percent of the cars must have a mobile phone in them. In urban areas, where traffic volumes are great, the system will work reliably with fewer cellular-phone users.

Radiolinja, for now the only operator in Finland with the service, said it is ready to expand the network and start testing in other European countries.

As is common when tracking cell phones is involved, there are privacy concerns. But project organizers say the only information recorded by the system is a random number linked to a cellular phone, the distance traveled, and the time it took.

There is no method, even in theory, to later link the identifying number with a particular mobile phone, Radiolinja said.